Respiratory Pathophysiology

Classifications of Respiratory Disorders

Classifications of Respiratory Disorders

• Acute
• Chronic
• Obstructive
• Restrictive

The pulmonary system and the cardiovascular system are _____

inextricably linked

•Cardiovascular problems often lead to ________ symptoms

pulmonary

Signs and Symptoms of Pulmonary Disease

• Dyspnea
• Cough
• Abnormal Sputum
• Abnormal Breathing Patterns
• Hypoventilation
• Hyperventilation
• Cyanosis
• Clubbing
• Pain

Dyspnea

discomfort with breathing

What is the subjective component of Dyspnea

severity of physiological derangement may not correlate with patients report of symptom severity

What is the most common respiratory and cardiac symptom

dyspnea

Dyspnea is a catch all term for

shortness of breath (SOB), chest tightness, increased work of breathing (WOB)

There is a physiologic component (sensory) and a neuro/psychological component to ______ (affective)

Dyspnea

_________ component (sensory) to Dyspnea

physiologic

___________ component (affective) to Dyspnea

neuro/psychological

What sensory receptors are involved in Dyspnea

• stretch receptors in lungs
• irritant receptors
• J-receptors
• central and peripheral chemoreceptors
• motor cortex

Signs and symptoms associated with dyspnea

• nostril flaring
• accessory muscle use
• supra-costal or intercostal retractions
• sub-costal retractions

What are supra-costal or intercostal retractions

(pulling back of supra-costal or intercostal spaces [pediatrics]

What are sub-costal retractions

pulling back of tissue between ribs) [lung parenchymal disease]

Retractions

Types of Dyspnea

dyspnea on exertion

dyspnea with exercise

Types of Dyspnea

orthopnea

dyspnea associated with heart failure and supine (abdominal contents compression diaphragm

Types of Dyspnea

paroxysmal nocturnal dyspnea

awake from sleep to gasp for air (with cardiac/pulmonary issues)

Define a Cough

explosive expiration of air against a closed glottis

A cough is a ________ reflex

protective

What are some of receptors for cough reflex stimulation located throughout the body

• mechanical
• chemical
• respiratory tract (more receptors in proximal airway, than distal airway)
• pericardium
• esophagus
• diaphragm
• stomach

In the respiratory tract there are more cough reflex receptors in ________ airway, than _______ airway

proximal
distal

Steps of a cough

•irritant receptors in airway are stimulated —> afferent signal via vagus nerve —> CNS (nucleus tractus solitarius)—> efferent signals via vagus, phrenic, and spinal motor nerves —>
1) inspiration of air
2) closure of glottis and vocal cords
3) contraction of expiratory muscles —> opening of glottis

Abnormal sputum is different by

• color
• consistency
• amount
• odor
• hemoptysis

Hemoptysis

expectoration of blood

What does hemoptysis indicates

infection or inflammation

Eupnea

normal breathing

Tachypnea

increased respiratory rate

Bradypnea

decreased respiratory rate

Apnea

absence of breathing

Hyperpnea

normal rate, increased depth of respirations

Cheyne-Stokes

gradual increases and decreases in respirations with periods of apnea

Biot's

rapid, deep respirations (gasp) with short pauses between

Kussmaul's

tachypnea with hyperpnea

Apneustic

prolonged inspiratory phase with shortened expiratory phase

breathing patterns

Hypoventilation

inadequate alveolar ventilation (minute ventilation) in relation to metabolic demands

Hypoventilation is caused by

either alterations in pulmonary mechanics or neurological control of breathing

Hypoventilation can be difficult to

detect visually unless severe

Hyperventilation

excess alveolar ventilation (minute ventilation) in relation to metabolic demands

Hyperventilation caused by

anxiety, pain, hypoxemia, or neurological injury

Cyanosis

bluish discoloration of skin and mucus membranes caused by increased levels of deoxygenated hemoglobin in blood

(deoxygenated blood is actually _____, not _______)

dark red
blue

hypoxemia must be ______ to notice

severe

Peripheral Cyanosis

results from peripheral vasoconstriction (Raynaud's, high dose vasopressors)

Central Cyanosis

results from decreased arterial oxygen tension (PaO2)

Clubbing

bulbous enlargement of distal segments of digits (fingers or toes)

Clubbing of the nail bed hypertrophy is related to

chronic hypoxemia

What are some disease that can lead to clubbing of the fingers?

cystic fibrosis
pulmonary fibrosis
bronchiectasis
congenital heart disease

What are typical characteristics of pain in the respiratory center

sharp or stabbing

Pain caused by ________ in the respiratory system

irritation of the nerve endings

What are some causes of pain in the respiratory system

• pleural pain
• tracheitis
• bronchitis
• pain from the muscles and bones of the rib cage

________ increases pain from rib fractures significantly

muscle spasms

What is the best way to treat muscle spasms from rib fractures

best to treat with muscle relaxers

Conditions Caused by Pulmonary Disease or Injury

• Hypercapnia
• Hypoxemia
• Hypoxia
• Respiratory Failure

Hypercapnia

increase concentration of CO2 in the arterial blood

Hypercapnia is caused by ( the patho)

increased CO2 production or decreased CO2 removal (i.e. hypoventilation)

List some examples of possible causes of Hypercapnia

• depression or respiratory centers
• disease of the medulla (infection or trauma)
• spinal cord abnormalities
• neuromuscular junction diseases
• thoracic cage injuries
• obstruction of large airways (tumors, sleep apnea)
• increased physiologic dead space (emphysema)

What are some complications from hypercapnia

• electrolyte disturbances
• dysrhythmias
• altered mental status
• increased intracranial pressure
• hypoxemia

Hypoxemia

reduced concentration of oxygen in the arterial blood (PaO2)

hypoxemia is not the same as hypoxia but can be one of many indicators of

decreased oxygen saturation

PaO2 measures

the small amount of oxygen that is carried in a dissolved form in the blood

Oxygen content blood =

[(Sa02 x 1.34 x Hb) + (0.003 x PaO2)]
[(99% x 1.34 x 13) + (0.003 x 100)]
[17.25] vs [0.3]

Causes of hypoxemia can be determined by

the ratio of alveolar oxygen (PAO2) and arterial oxygen (PaO2)

Mechanisms of hypoxemia:

• impaired oxygen delivery to alveoli
• impaired diffusion of oxygen from alveoli into blood
• impaired perfusion of pulmonary capillaries

Hypoxemia: impaired oxygen delivery to alveoli causes?

• decreased FiO2
• decreased alveolar ventilation

Hypoxemia: impaired diffusion of oxygen from alveoli into blood causes?

• V/Q mismatch
• altered alveolo-capillary membrane

Hypoxia

reduced oxygen delivery to tissues

Hypoxia can be caused by...

decreased oxygen saturation
anemia
hypoxemia
perfusion

Respiratory failure

inadequate gas exchange

Respiratory failure defined as

• PaO2 ≤ 50 mmHg
• PaCO2 ≥ 50 mmHg with pH ≤ 7.25

Respiratory failure can be caused because injuries to what areas

• lungs
• airways
• chest wall
• indirect injury to other systems related to respiratory system (brain, kidneys, liver, heart, etc.)
• can be acute or chronic
• if failure is hypercapnia type then —> inadequate ventilation
• if failure is hypoxemic type then —> inadequate exchange of oxygen

______ and ______ can either cause new onset respiratory failure or exacerbate existing respiratory failure

surgery and anesthesia

______ is key to respiratory failure

Prevention

Restriction of the Chest Wall

things that can interfere with chest wall motion (reducing tidal volume)

Examples of things that can cause restriction of the chest wall

• deformities (pectus excavatum, pectus carinatum, scoliosis)
• trauma (broken ribs, flail chest)
• increased mass (adipose tissue)
• decreased muscle mass (muscular dystrophy, Guillain-Barre syndrome)

Body compensates for decreased tidal volume by ________, but can only compensate so much

increasing respiratory rate

Restrictions of the Pleural Cavity

pneumothorax

Pneumothorax

presence of air or gas in the pleural space

Pneumothorax caused by

rupture in the visceral pleural (surrounding the lungs) or the parietal pleura (surrounding the chest wall)

What is the rupture in a visceral pleural

surrounding the lungs

What is the rupture in a parietal pleura

surrounding the chest wall

Pneumothorax: during inspiration...

air is drawn into space between the visceral and parietal pleura —> negative pressure between pleural space is lost —> force of elastic recoil of lung > pleural rigidity —> lung collapse

What are some Restrictions of the Pleural Cavity

Pneumothorax

Pleural Effusions

Types Pneumothorax

• closed
• open
• tension

Types Pneumothorax- Closed

• no communication between pleural cavity and atmosphere

• typically less severe

Types Pneumothorax- Closed

• ______ between pleural cavity and atmosphere

NO communication

Types Pneumothorax- Closed

• typically _______ severe

less

Types Pneumothorax- Open

• communication between pleural cavity and atmosphere
• need one way valve dressing to prevent entrainment of more air into pleural space, but allows existing air to escape

Types Pneumothorax- Open

______ between pleural cavity and atmosphere

communication

Types Pneumothorax- Open

Needs what type of dressing

need one way valve dressing to prevent entrainment of more air into pleural space, but allows existing air to escape

Types Pneumothorax- Tension

• communication between pleural cavity and atmosphere allows air into pleural space BUT does not let air out.
• increasing intrapleural pressure forces mediastinal structures to shift to side with less pressure (normal lung)
• vascular structures within the thoracic space are compressed
• decreased venous return
• decreased CO
• decreased BP
• Airway is compressed
• tracheal shift
• compression of non-affected lung

Types Pneumothorax- Tension

communication between pleural cavity and atmosphere allows _______

air into pleural space BUT does not let air out

Types Pneumothorax- Tension

_____ intrapleural pressure forces mediastinal structures to __________

increasing
shift to side with less pressure (normal lung)

Types Pneumothorax- Tension

•vascular structures within the thoracic space are compressed... causing decreased (3 things)

venous return
CO
BP

Types Pneumothorax- Tension

Airway is _____.... causing

• _____ shift

• compression of ______ lung

compressed
tracheal
non-affected